*2.4. Diamond Sharpening Solid Ceramic End Mills*

Multi-stage diamond sharpening was performed on a Helitronic Micro multi-axis machine from Walter Maschinenbau GmbH (Tübingen, Germany) to manufacture solid

end mills from ceramic rod-blanks with the required design and geometric parameters. The sequence of the main operations of forming ceramic cutters is illustrated in Figure 5.

**Figure 5.** The main stages sequence for diamond sharpening solid ceramic end mill: (**a**) the relative position of the machine spindle and the workpiece when forming a ceramic end mill; (**b**) a ceramic rod; (**c**) grinding the helical chip grooves with a tapered disk; (**d**) grinding the rake face at the end with a cup-bevel wheel; (**e**) grinding the secondary relief surface at the end with a cup-bevel wheel; (**f**) grinding the primary relief surface at the end with a cup-bevel wheel; (**g**) grinding the secondary relief surface at the periphery with the cup-bevel wheel; and (**h**) grinding the secondary relief surface on the transitional radius section with the cup-bevel wheel.

The information on chosen cutting modes and the type of grinding wheels used are given in Table 2. The given technological operations and processing modes were selected based on ensuring high-precision execution of ceramic end mills, their profile, geometric dimensions, and high cleanliness of the tool surfaces (0.32–0.5 μm in *Ra* surface roughness parameter). Particular attention was paid to quality control of the cutting edges of ceramic end mills and minimization of micro-chips that significantly reduce the tool life. The manufactured end mills' control was carried out on a non-contact precision measuring device, Helicheck Plus, manufactured by Walter Maschinenbau GmbH (Tübingen, Germany).


**Table 2.** Modes of ceramic end mill diamond grinding and the type of used grinding wheels.
